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J Gauger

Publications and source records attributed to J Gauger.

26 records · Page 2Linked to original sources
PubMed1995

[Phased-array superficial coil and breath holding technique in MRI of the liver. Comparison of conventional spin echo sequences with rapid fat suppressing gradient echo and turbo-spin sequences].

PURPOSE: To determine the efficacy of fast MRI techniques using a tailored imaging design (breathhold and array-surface coil), conventional T1-, T2-weighted spin-echo (SE) sequences and breathhold gradient-echo (GRE) T1- and breathhold fast SE T2-weighted images were compared. METHODS: 20 patients with proven focal liver lesions were studied on a 1.5 Tesla system. Conventional SE T1- and T2-weighted imaging, as well as GRE T1- and fast SE T2-weighted imaging was performed. Fast imaging was done during breathhold using an array-surface coil. For all sequences signal-to-noise ratios (S/N) and liver-to-lesion-contrast ratios (L/L) were measured and statistically compared. In addition, two blinded readers qualitatively evaluated all images, using a score system regarding artifacts (breathing, pulsation), number of lesions, and over-all image quality. RESULTS: Regarding image quality parameters, S/N and L/L, there was no significant (p > 0.05) difference between the conventional and fast imaging techniques. However, GRE imaging was superior (84.8%) to conventional imaging for breathing and pulsation artifacts, while fast SE T2 imaging was equal regarding breathing artifacts, but superior (51.5%) regarding pulsation artifacts. The number of detected hepatic lesions was identical in all sequences. CONCLUSION: The fast MRI techniques demonstrated a superiority to conventional imaging regarding image quality and presence of artifacts. Therefore, fast imaging techniques can replace conventional techniques, at least in patients that can sufficiently sustain breathing.

Artifacts↗
PubMed1995

[Fast and ultra-fast sequences in MRI of the pelvis and retroperitoneum].

Fast and ultrafast sequences are crucial prerequisite for optimum diagnostic impact in magnetic resonance (MR) imaging of the pelvis and retroperitoneum. In MR imaging of the pelvis, heavily T2-weighted fast turbo spin echo (TSE) sequences with acquisition times of 2-4 min have widely replaced time-consuming conventional T2-weighted SE sequences due to substantial time savings and better image quality. Fast and ultrafast gradient recalled echo (GRE) sequences are the basis of dynamic contrast-enhanced studies. In MR imaging of the retroperitoneum, fast and ultrafast sequences currently play the most important role as they allow for breath-hold acquisition of a sufficient number of images free of motion artifacts. The current roles of TSE, tubo gradient spin echo (TGSE), GRE and echoplanar imaging (EPI) sequences in MR imaging of the pelvis and retroperitoneum is discussed.

Artifacts↗
PubMed1994

Bubbles in the belly: imaging of cystic mesenteric or omental masses.

The purpose of this article is to familiarize radiologists with the spectrum of "bubbles in the belly," including the current histologic classification of mesenteric or omental cysts. Although mesenteric and omental cystic masses are uncommon lesions, radiologists should be familiar with them as well as with other anomalies that can manifest as these cysts. The first step in diagnosing a cystic abdominal mass is to determine the organ from which the mass originates. The most common type of mesenteric or omental cyst is lymphangioma, but other types encountered include the enteric duplication cyst, the enteric cyst, the mesothelial cyst, and the nonpancreatic pseudocyst. Other cystic lesions that may be located in the mesentery or omentum include cystic mesothelioma, cystic spindle cell tumor, and cystic teratoma. Because of the overlap in imaging features of mesenteric or omental cysts and other cystic masses, histologic analysis is usually necessary to establish a diagnosis. The major role of the radiologist is to document the cystic nature of these abdominal masses and their mesenteric or omental origin.

Cysts↗
PubMed1993

Changes of soft-tissue water examined with magnetic resonance and electrical impedance tomography: an in vivo experiment.

The purpose of this study was the examination of short-term changes in soft-tissue water under in vivo conditions. In 12 healthy volunteers the water distribution of a selected slice of the lower limb was examined after change of position and rapid infusion of 0.9% saline solution. Two methods were used for data acquisition: magnetic resonance imaging (MRI) (Repetition Time (TR) = 1600 msec, Inversion Time (TI) = 300 msec, Echo Time (TE) = 22 msec) and electrical impedance tomography (EIT). In orthostatic equilibrium all 12 volunteers demonstrated changes of MR signal intensity and resistivity in the range of 12% and 7%, respectively. After infusion, mean changes of signal intensity and resistivity were 7% and 4%, respectively. The overall correlation of MRI and EIT was -0.96 (p < 0.001). Results indicate that inversion recovery sequences are a sensitive method of detecting in vivo changes of water distribution in selected areas of the body.

Adult↗
PubMed1991

Classification of the free fluid reservoir in the calf by electrical impedance tomography.

The Electrical impedance tomography computes images of resistivity distribution which allow to analyse the body fluid content. The Sheffield system, Applied Potential Tomography (APT) was chosen to examine fluid shifts in the calf following body postural change, saline infusion (FL), and lower body negative pressure stress (LBNP). The APT allows the detection of differently reacting regions in the tomogram. The overall images of APT showed an exponential resistivity increase after the body position change from upright to 6 degrees head down tilt (HDT). During LBNP the pattern of the APT images looked the same as during FL. Both showed a resistivity decrease in the overall images. The outer surface showed a different magnitude of resistivities compared to the inner region in all experiments. A comparison of the overall APT images with the tomograms simultaneously obtained by NMR in one test subject showed the same tendency. This leads to the conclusion that the changes in the fluid reservoir of the calf may be classified by electrical impedance tomography.

Adult↗
PubMed1988

[Molecular biological properties of the AIDS virus].

Genetic information on the AIDS virus, which belongs to the family of retroviruses, is encoded in a single-strand RNA. After infection of the target cell, its genomic RNA is transcribed into DNA by the reverse transcriptase. Subsequently, the DNA can be integrated into the host genome. This viral genome encodes the envelope proteins, the core proteins and the viral enzymes. There are additional genes coding for products which have regulatory functions and determine the interaction between virus and host cell. The replication cycle of the AIDS virus begins with infection of the target cell. After transcription by the reverse transcriptase, the genetic viral information may remain latent or may, under certain circumstances, lead to the expression of viral components which can be assembled at the cell membrane. New viruses are then formed by budding. Theoretically, each step in the viral replication cycle could serve as a target of therapeutic intervention. Up to now, only a few compounds have been investigated in clinical studies.

Acquired Immunodeficiency Syndrome↗
PubMed1978

Sensory dysfunction in children who toe walk.

In order to formulate a hypothesis regarding the etiology of toe walking, the sensory processing abilities of 17 mentally retarded children who toe walk were examined. A galvanic skin response was used to compare reactions of the mentally retarded children and a group of normal children to a variety of sensory stimuli. Galvanic skin response testing did not reveal significant differences between the two groups in processing sensory input. Scores of the mentally retarded children from a postrotary nystagmus test were compared to values for normal children of the same age, and the results indicated that vestibular dysfunction was present in all of the subjects. We hypothesize that children may toe walk to increase somatosensory input to the lateral vestibular nucleus (Deiter's) and the lateral vestibulospinal tract to facilitate support tone in the lower extremities during walking.

Acoustic Stimulation↗